docs: remove unused NonNull imports

Signed-off-by: Martin Kröning <[email protected]>

Author: mkroening

src/volatile_ptr/macros.rs

@@ -6,7 +6,6 @@
 ///
 /// ```
 /// use volatile::{VolatilePtr, map_field};
-/// use core::ptr::NonNull;
 ///
 /// struct Example { field_1: u32, field_2: u8, }
 /// let mut value = Example { field_1: 15, field_2: 255 };
@@ -20,7 +19,6 @@
 /// Creating `VolatilePtr`s to unaligned field in packed structs is not allowed:
 /// ```compile_fail
 /// use volatile::{VolatilePtr, map_field};
-/// use core::ptr::NonNull;
 ///
 /// #[repr(packed)]
 /// struct Example { field_1: u8, field_2: usize, }

src/volatile_ptr/operations.rs

@@ -100,7 +100,6 @@ where
     ///
     /// ```rust
     /// use volatile::VolatilePtr;
-    /// use core::ptr::NonNull;
     ///
     /// let mut value = 42;
     /// let mut volatile = unsafe { VolatilePtr::new((&mut value).into()) };
@@ -124,7 +123,6 @@ where
     ///
     /// ```rust
     /// use volatile::VolatilePtr;
-    /// use core::ptr::NonNull;
     ///
     /// let mut value = 42;
     /// let mut volatile = unsafe { VolatilePtr::new((&mut value).into()) };
@@ -148,7 +146,6 @@ where
     ///
     /// ```
     /// use volatile::VolatilePtr;
-    /// use core::ptr::NonNull;
     ///
     /// let mut value = 42;
     /// let mut volatile = unsafe { VolatilePtr::new((&mut value).into()) };
@@ -188,7 +185,6 @@ where
     ///
     /// ```
     /// use volatile::VolatilePtr;
-    /// use core::ptr::NonNull;
     ///
     /// let mut value = 5;
     /// let mut volatile = unsafe { VolatilePtr::new((&mut value).into()) };
@@ -247,7 +243,6 @@ where
     ///
     /// ```
     /// use volatile::VolatilePtr;
-    /// use core::ptr::NonNull;
     ///
     /// let mut value: i16 = -4;
     /// let mut volatile = unsafe { VolatilePtr::new((&mut value).into()) };
@@ -268,7 +263,6 @@ where
     ///
     /// ```
     /// use volatile::{VolatilePtr, map_field};
-    /// use core::ptr::NonNull;
     ///
     /// struct Example { field_1: u32, field_2: u8, }
     /// let mut value = Example { field_1: 15, field_2: 255 };

src/volatile_ref.rs

@@ -226,7 +226,6 @@ where
     ///
     /// ```
     /// use volatile::VolatileRef;
-    /// use core::ptr::NonNull;
     ///
     /// let mut value: i16 = -4;
     /// let mut volatile = VolatileRef::from_mut_ref(&mut value);
@@ -247,7 +246,6 @@ where
     ///
     /// ```
     /// use volatile::{VolatileRef};
-    /// use core::ptr::NonNull;
     ///
     /// #[derive(Clone, Copy)]
     /// struct Example { field_1: u32, field_2: u8, }